<?php

//加密函数
function passport_encrypt($txt, $key) {
	srand((double)microtime() * 1000000);
	$encrypt_key = md5(rand(0, 32000));
	$ctr = 0;
	$tmp = '';
	for($i = 0;$i < strlen($txt); $i++) {
	   $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
	   $tmp .= $encrypt_key[$ctr].($txt[$i] ^ $encrypt_key[$ctr++]);
	}
	return base64_encode(passport_key($tmp, $key));
}
	echo passport_encrypt('123456','1');
//解密函数
function passport_decrypt($txt, $key) {
	$txt = passport_key(base64_decode($txt), $key);
	$tmp = '';
	for($i = 0;$i < strlen($txt); $i++) {
	   $md5 = $txt[$i];
	   $tmp .= $txt[++$i] ^ $md5;
	}
	return $tmp;
}

function passport_key($txt, $encrypt_key) {
	$encrypt_key = md5($encrypt_key);
	$ctr = 0;
	$tmp = '';
	for($i = 0; $i < strlen($txt); $i++) {
	   $ctr = $ctr == strlen($encrypt_key) ? 0 : $ctr;
	   $tmp .= $txt[$i] ^ $encrypt_key[$ctr++];
	}
	return $tmp;
	}
?>